Accident Debus-Casst-Snoshoo (Modified Cassutt) N102MB,
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ASN Wikibase Occurrence # 22713
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Date:Saturday 6 September 2008
Type:Silhouette image of generic CASS model; specific model in this crash may look slightly different    
Debus-Casst-Snoshoo (Modified Cassutt)
Owner/operator:Erica Simpson
Registration: N102MB
MSN: DMB-001
Total airframe hrs:911 hours
Fatalities:Fatalities: 1 / Occupants: 1
Aircraft damage: Substantial
Location:Reno Stead Airport (4SD), Reno, NV -   United States of America
Phase: Manoeuvring (airshow, firefighting, ag.ops.)
Departure airport:Reno, NV (4SD)
Destination airport:
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
During an air race class qualification flight, the pilot was performing a series of maneuvers required to obtain a class license. During a required roll maneuver, as the airplane passed through about 90 to 120 degrees of roll at an estimated speed of 220 to 230 miles per hour, the right wing separated from the airframe, followed almost immediately by the left wing. The amateur built experimental airplane was fitted with an in-flight adjustable pitch trim system, which was a deviation from the original ground-only trim adjustment design. The trim system, designed by the airplane's builder, allowed the pilot to adjust the pitch trim by moving the horizontal stabilizer in flight. The in-flight system was composed of a lever attached to the fuselage structure, and its movement was restricted with friction washers between the fuselage and the lever. Full travel of the lever resulted in one inch of vertical movement of the horizontal stabilizer's leading edge. The manufacturer of the airframe kit stated that the trim system installed on the accident airplane was not of their design. They further stated that any movement of the horizontal stabilizer during an abrupt maneuver could produce an extremely high amount of G-forces and possibly exceed the structural design limits of the airplane. Post accident examination of the wreckage revealed no evidence of pre-existing anomalies with the airframe or flight control system. The wooden wing spar was tested and found to be of proper grade wood. No anomalies were noted with the spar material. The fracture surfaces of both the left and right wing forward wing spars were consistent with a "substantial upward force" and overload. It is unknown if the horizontal trim system was moved in-flight by commanded or uncommanded action. Amateur built airplanes with experimental certificates are not subject to the airworthiness standards in 14 CFR Parts 23 and 47 of the Federal Aviation Regulations, and builders and owners are free to make any modifications to the airplane at will.
Probable Cause: The movement of the airplane’s modified horizontal stabilizer trim system during an intentional high speed aerobatic maneuver that resulted in exceedence of the design stress limits of the airplane and an in-flight structural failure. Contrubuting to the accident was that the builder’s deviation from the airplane designer's original trim system.



Accident investigation:
Investigating agency: NTSB
Report number: SEA08FA196
Status: Investigation completed
Duration: 1 year
Download report: Final report


(c) NTSB

Revision history:

07-Sep-2008 11:01 angels one five Added
08-Sep-2008 09:32 jorgetadeu7 Updated
23-Jun-2009 12:02 harro Updated
21-Dec-2016 19:14 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
21-Dec-2016 19:16 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
21-Dec-2016 19:20 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
03-Dec-2017 12:05 ASN Update Bot Updated [Operator, Other fatalities, Nature, Departure airport, Destination airport, Source, Narrative]

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